After performing illumination measurement readings, some measurements exceeded the threshold dictated by Option 3, Approach 1: Difference in Illumination levels is 20 percent or less. The uncertainty of the light meter used is over six times the captured light level, which could be a result of the inability of a calibrated meter to obtain accurate readings due to low light levels on the project. Even though some measurements exceed the Option 3 threshold, we feel that the project's low light levels meet the intent of the credit. Can readings that are exceeded by the uncertainty of a calibrated light meter be excluded from Option 3?
The proposed strategy of excluding readings that are exceeded by the light meter uncertainty is not acceptable for SSc8 Light Pollution Reduction. Due to the calculation method of the uncertainty of the light meter, in low light situations where the difference in readings with the exterior lights on and off is less than the uncertainty of the meter this would apply to a far greater number of data points than those with minimal differences in lighting.
As an alternative, projects may demonstrate that measurement points meet the values listed in New Construction SSc8 Light Pollution Reduction for the project’s lighting zone. A combination of strategies is allowed, however each measurement point must comply with one of the strategies, with no exceptions or averaging across data points.